/*    serialio.c     allows user Interactive C programs    to send and receive serial data*/    /* allows user programs to receive serial data */void disable_pcode_serial(){   poke(0x3c, 1);}/* allows board interaction with IC on host computer */void enable_pcode_serial(){   poke(0x3c, 0);}void serial_putchar(int c){   /* wait until serial transmit empty */   while (!(peek(0x102e) & 0x80));   /* send character */   poke(0x102f, c);}int serial_getchar(int c){   /* wait until a character is received */   while (!(peek(0x102e) & 0x20));   /* return it */   return peek(0x102f);}